Erbium-Doped Fibre Quantum Memory for Chip-Integrated Quantum-Dot Single Photons at 980 nm

TL;DR

This paper demonstrates a coherent hybrid quantum interface between a chip-integrated quantum dot and an erbium-doped fiber quantum memory at 980 nm, enabling efficient storage and retrieval of single photons for quantum networks.

Contribution

First experimental realization of a hybrid interface between a quantum dot and erbium-doped fiber quantum memory at 980 nm, without spectral tuning of the quantum dot.

Findings

Successful storage and recall of single photons in erbium-doped fiber quantum memory.

Demonstration of broadband multimode quantum memory with 8 GHz bandwidth.

Quantum dot emission directly compatible with solid-state quantum memory without spectral tuning.

Abstract

The realization of long-distance quantum communication and the envisioned quantum internet relies on coherent hybrid light-matter interfaces connecting quantum light emitters with quantum memory (QM) systems. Unlike probabilistic photon pair sources such as spontaneous parametric down-conversion, deterministic quantum light emitters enable the on-demand production of pure and bright single and entangled photons, essential for scalable quantum networks. In this work, we present the first experimental realization of a coherent hybrid light-matter interface between a chip-integrated InAsP/InP nanowire quantum dot (QD) and a solid-state QM based on Er$^{3+}$ ions doped in a glass silica fiber (erbium-doped fiber, EDF). The emission spectrum of the InAsP/InP nanowire QD aligns with the absorption bandwidth of the EDF at 980 nm at cryogenic temperatures, allowing efficient interaction between the two systems. To demonstrate this, we present a spectroscopic characterization of the $^{4}I_{15/2} \leftrightarrow ^{4}I_{11/2}$ optical transition in EDF at 980 nm. Our measurements reveal substantial inhomogeneous broadening of this optical transition and a long spin population lifetime, underscoring EDFs potential for broadband QM implementation. We implement an 8 GHz bandwidth multimode QM based on the Atomic Frequency Comb protocol, enabling the storage and retrieval of 59 weak coherent pulses. Furthermore, we characterize single-photon emission from an InAsP/InP nanowire QD at 980 nm and demonstrate its deterministic storage and recall in the EDF QM. Notably, this is achieved without spectral tuning of the QD emission, demonstrating its direct compatibility with a solid-state QM.